In contrast to a traditional rigid kinematic chain which achieves a bending motion by rotating to each other at a joint, a flexible continuum mechanism achieves a bending deformation of a distal structure by the deformation of a proximal structure. In the flexible continuum mechanism, the main body of the structure is also a driving transfer structure, so that an extremely high degree of freedom configuration can be realized in a small-size space. The flexible continuum mechanism has the characteristics of a compact structure, high flexibility, flexible and safe contact guarantee, etc., and thus is widely used in the research and development of medical instruments, such as flexible manipulator arms, endoscopes and controllable catheters, and new special equipment such as industrial deep cavity detection endoscopes, and flexible robotic arms.
In the medical or industrial field, a distal end of the flexible continuum mechanism is mostly used to extend into a winding and complex deep cavity environment, the distal end thereof is mostly invisible or partially visible, and therefore, a posture feedback of the flexible continuum mechanism is an important safeguard for its reliability and safety of use. However, in the flexible continuum mechanism with a structural backbone as the main body, a bending motion thereof is realized by pushing and pulling the structural backbone. As the bending motion does not have a clear rotary joint, the feedback of a bending posture of the flexible continuum mechanism cannot be directly realized by an angle sensor disposed at the joint in the rigid kinematic chain, and at the same time, there is no posture feedback sensor especially for the flexible continuum mechanism.